Reliability of side-to-side sonographic cross-sectional area measurements of upper extremity nerves in healthy volunteers

Sonographic Evaluation of the Lateral Femoral Cutaneous Nerve: Single-Institution Experience and Pictorial Review

ABSTRACT

The location of the lateral femoral cutaneous nerve (LFCN) makes it susceptible to injury with trauma, external compression, and iatrogenic injury. The objectives of this study were to report the single-institution efficacy of LFCN visualization on ultrasound (US), define the clinical characteristics of patients with LFCN palsy, and describe sonographic appearances of LFCN abnormalities by pictorial review. A retrospective chart review of LFCN cases evaluated using US at a single institution was performed, documenting rate of visibility on US, mode of nerve injury, and US imaging findings. Nerve visibility rates on US were correlated with magnetic resonance imaging (MRI) when both modalities were used. Imaging findings were confirmed with clinical/surgical history and follow-up. Retrospective review found that 170 patients underwent US for LFCN evaluation in the last 10 years. Injury was associated with surgical intervention in 56% of cases, and perineural scarring was the most common pathology described using US. Lateral femoral cutaneous nerve was visible on US in 97% of cases; MRI visualized LFCN in 60%. Chart review showed US as an effective tool in evaluating LFCN pathology, with a higher visualization rate than MRI. Through pictorial review, the array of LFCN pathology sonographically detectable is demonstrated.

Ulnar neuropathy

Ulnar neuropathy at the elbow is the second most common compressive neuropathy. Less common, although similarly disabling, are ulnar neuropathies above the elbow, at the forearm, and the wrist, which can present with different combinations of intrinsic hand muscle weakness and sensory loss. Electrodiagnostic studies are moderately sensitive in diagnosing ulnar neuropathy, although their ability to localize the site of nerve injury is often limited. Nerve imaging with ultrasound can provide greater localization of ulnar injury and identification of specific anatomical pathology causing nerve entrapment. Specifically, imaging can now reliably distinguish ulnar nerve entrapment under the humero-ulnar arcade (cubital tunnel) from nerve injury at the retro-epicondylar groove. Both these pathologies have historically been diagnosed as either "ulnar neuropathy at the elbow," which is non-specific, or "cubital tunnel syndrome," which is often erroneous. Natural history studies are few and limited, although many cases of mild-moderate ulnar neuropathy at the elbow appear to remit spontaneously. Conservative management, perineural steroid injections, and surgical release have all been studied in treating ulnar neuropathy at the elbow. Despite this, questions remain about the most appropriate management for many patients, which is reflected in the absence of management guidelines.

Ultra-high-definition (22 MHz) ultrasound of the ulnar nerve: additional value and normative data

We studied 30 healthy volunteers (60 arms), categorized into three age groups with equal numbers to verify if a 22 MHz compared with a 15 MHz ultrasound transducer has additional value for studying the intraneural architecture of the ulnar nerve throughout its course. At six sites, there were no differences in cross-sectional area measurements between the two transducers. With both, the cross-sectional area was significantly larger at the medial epicondyle compared with the other sites and smaller at the mid-forearm and Guyon's canal compared with the mid-upper arm. With higher age the cross-sectional area significantly increased. Significantly more fascicles were visible distal to the medial epicondyle compared with more proximal sites, as well as in men compared with women. Finally, higher body weight was related to a significantly smaller number of fascicles being seen. A 22 MHz transducer depicts more details of the intraneural architecture than a 15 MHz transducer. Our data can be used as normative data or reference values in analysing ulnar nerve pathology.Level of evidence: II.

Ultrasound morphometry of the cervical vagus nerve for daily clinical practice: Reference values for cross sectional area and fascicle count

INTRODUCTION

High resolution ultrasound (US) of the cervical vagus nerve (CVN) is clinically relevant in the diagnostic workup and during neurostimulation therapy of several neurologic diseases. This prospective study aims to provide reference data of the cross-sectional area (CSA) and fascicle count of the normal CVN and to investigate their possible association with anthropometric data in a large cohort of patients.

METHODS

A total of 657 CVNs in 330 individuals without history of neurological disease were examined using US (7-15Mhz). The CVN fascicle count and CSA inside the hyperechoic epineurium at the level of the thyroid lobes were measured. Three CSA measurements were performed to calculate the mean value. Anthropometric data were recorded.

RESULTS

The mean fascicle count was 2.4 ± 1.1 (right) and 2 ± 1 (left) (paired t- test, p < 0.001). Two CVN patterns were identified: A single hypoechoic fascicular structure (26.2 % right, 36.3 % left) and a honeycomb structure of 2-6 discrete fascicles (72.3 % right, 63.7 % left). Right CVN mean CSA was larger compared to left (2.3 ± 1 mm2 and 1.8 ± 0.8 mm2 respectively, t-test, p-0.000). There was no difference in the CSA values between sex and no correlation to age or height. A positive correlation between the CSA and weight and BMI was found (Pearson's correlation, p = 0.01 right and p = 0.05 left).

CONCLUSION

The right CVN has larger CSA and contains more fascicles than the left. CVN is usually mono- or oligo-fascicular with a honeycomb appearance. The CSA increased with increasing BMI but no age and sex specific differences were noted.

Deep branch of the radial nerve: effect of pronation/supination on longitudinal nerve alignment

OBJECTIVE

To evaluate the effect of maximal pronation and supination of the forearm on the alignment and anatomic relationship of the deep branch of the radial nerve (DBRN) at the superior arcade of the supinator muscle (SASM) by using high-resolution ultrasound (HRUS).

MATERIALS AND METHODS

In this cross-sectional study, HRUS in the long axis of the DBRN was performed in asymptomatic participants enrolled from March to August 2021. DBRN alignment was evaluated by measuring angles of the nerve in maximal pronation and maximal supination of the forearm independently by two musculoskeletal radiologists. Forearm range of motion and biometric measurements were recorded. Student t, Shapiro-Wilk, Pearson correlation, reliability analyses, and Kruskal-Wallis test were used.

RESULTS

The study population included 110 nerves from 55 asymptomatic participants (median age, 37.0 years; age range, 16-63 years; 29 [52.7%] women). There was a statistically significant difference between the DBRN angle in maximal supination and maximal pronation (Reader 1: 95% CI: 5.74, 8.21, p < 0.001, and Reader 2: 95% CI: 5.82, 8.37, p < 0.001). The mean difference between the angles in maximal supination and maximal pronation was approximately 7° for both readers. ICC was very good for intraobserver agreement (Reader1: r ≥ 0.92, p < 0.001; Reader 2: r ≥ 0.93, p < 0.001), as well as for interobserver agreement (phase 1: r ≥ 0.87, p < 0.001; phase 2: r ≥ 0.90, p < 0.001).

CONCLUSION

The extremes of the rotational movement of the forearm affect the longitudinal morphology and anatomic relationships of the DBRN, primarily demonstrating the convergence of the nerve towards the SASM in maximal pronation and divergence in maximal supination.

Sonographic peripheral nerve cross-sectional area in adults, excluding median and ulnar nerves: A systematic review and meta-analysis

INTRODUCTION/AIMS

Although electromyography remains the "gold standard" for assessing and diagnosing peripheral nerve disorders, ultrasound has emerged as a useful adjunct, providing valuable anatomic information. The objective of this study was to conduct a systematic review and meta-analysis evaluating the normative sonographic values for adult peripheral nerve cross-sectional area (CSA).

METHODS

Medline and Cochrane Library databases were systematically searched for healthy adult peripheral nerve CSA, excluding the median and ulnar nerves. Data were meta-analyzed, using a random-effects model, to calculate the mean nerve CSA and its 95% confidence interval (CI) for each nerve at a specific anatomical location (= group).

RESULTS

Thirty groups were identified and meta-analyzed, which comprised 16 from the upper extremity and 15 from the lower extremity. The tibial nerve (n = 2916 nerves) was reported most commonly, followed by the common fibular nerve (n = 2580 nerves) and the radial nerve (n = 2326 nerves). Means and 95% confidence interval (CIs) of nerve CSA for the largest number of combined nerves were: radial nerve assessed at the spiral groove (n = 1810; mean, 5.14 mm2 ; 95% CI, 4.33 to 5.96); common fibular nerve assessed at the fibular head (n = 1460; mean, 10.18 mm2 ; 95% CI, 8.91 to 11.45); and common fibular nerve assessed at the popliteal fossa (n = 1120; mean, 12.90 mm2 ; 95% CI, 9.12 to 16.68). Publication bias was suspected, but its influence on the results was minimal.

DISCUSSION

Two hundred thirty mean CSAs from 15 857 adult nerves are included in the meta-analysis. These are further categorized into 30 groups, based on anatomical location, providing a comprehensive reference for the clinician and researcher investigating adult peripheral nerve anatomy.

Reliability of ultrasound in the assessment of muscle thickness in critically ill children

INTRODUCTION

Ultrasound has been used to quantify and qualify muscle morphology in critically ill children and can detect changes in muscle thickness. The aim of this study was to assess the reliability of ultrasound measurement of muscle thickness in critically ill children and to compare the assessments made by an expert with those made by inexperienced sonographers.

MATERIAL AND METHODS

Cross-sectional observational study conducted in the paediatric intensive care unit of a tertiary care university hospital in Brazil. The sample included patients aged 1 month to 12 years who received invasive mechanical ventilation for at least 24 h. Ultrasound images of the biceps brachii/brachialis and quadriceps femoris were obtained by one experienced sonographer and several inexperienced sonographers. We assessed intrarater and inter-rater reliability by means of the intraclass correlation coefficient (ICC) and Bland-Altman plot analysis.

RESULTS

Muscle thickness was measured in 10 children with a mean age of 15.5 months. The mean thickness of the assessed muscles as 1.14 cm for the biceps brachii/brachialis (standard deviation [SD], 0.27) and 1.85 cm for the quadriceps femoris (SD, 0.61). The intrarater and inter-rater reliability were good for all sonographers (ICC > 0.81). The differences were small, there was no significant bias in the Bland-Altman plots and all measurements were within the limits of agreement, except for 1 measurement of biceps and quadriceps.

CONCLUSION

Sonography can be used in critically ill children to accurately assess changes in muscle thickness, even by different evaluators. More studies are needed to establish a standardised approach to the use of ultrasound for monitoring muscle loss in order to incorporate it in clinical practice.

The cross-sectional morphology of median nerve in carpal tunnel of healthy, adult population: A systematic review and meta-analysis

The cross-section area is a crucial parameter to assess peripheral neuropathy. The ultrasonographic evaluation of cross-section area of median nerve is a low-cost and readily available tool for diagnosis and assessment. However, the intra-nerve dimensional variability and its normative reference value in a healthy subject are missing. The current meta-analysis aims to capture the median nerve cross-section area for healthy subjects and generate a comprehensive ultrasonographic reference data set for each population.

METHODS

The full text of manuscripts were collected after short-listing the abstracts collected from search strategy. A quality assurance tool was used to capture the risk of bias of each study after reviewing the included manuscripts. The pooled estimate of cross-section area was stratified according to anatomical landmarks, sex, and ancestry.

RESULTS

A total of 97 observational studies dealt with 6679 wrists of healthy subjects were included. The pooled estimate of the cross-section area of median nerve at carpal tunnel inlet was 8.54mm² [95% CI: 8.34-8.74mm²]. The same pooled estimate at carpal tunnel outlet was 8.03mm² [95% CI: 7.46-8.60mm²]. Both these pooled estimates have significant correlation with mean age of population. Age and sex were two primary predictors of the cross-section of median nerve. The flattening ratio, circularity, and wrist-forearm ratio of median nerve were also computed.

CONCLUSION

These normative data could serve as a reference for assessing median nerve pathologies, including carpal tunnel syndrome. The ethnic variation of pooled estimate and heterogeneity will guide clinician set up the reference value for diagnostic criteria.

Cross-sectional Area Ratio of Median-to-Ulnar and Median-to-Superficial Radial Nerve at the Wrist for Diagnosis of Carpal Tunnel Syndrome

Objectives:

This study aimed to evaluate the diagnostic properties for carpal tunnel syndrome (CTS) of the median-to-ulnar cross-sectional area ratio (MUR) and the median-to-superficial radial cross-sectional area ratio (MRR).

Methods:

A case–control study was conducted. A physiatrist, blinded to the CTS status of the subjects, assessed the cross-sectional area of the median nerve (CSA-m), MUR, and MRR at the distal wrist crease for the CTS and control groups. The relationship of CSA-m, MUR, and MRR with CTS severity was tested using Spearman’s correlation. The overall diagnostic accuracy was determined using the area under the receiver operating characteristic curve (AUC). The cut-off values to diagnose CTS were chosen to achieve similar values for sensitivity and specificity.

Results:

There were 32 hands in the CTS group and 33 hands in the control group. The correlations of CSA-m, MUR, and MRR with CTS severity were 0.66, 0.56, and 0.34, respectively. The AUCs of CSA-m, MUR, and MRR were 0.86 (95%CI: 0.77–0.95), 0.79 (0.69–0.90), and 0.69 (0.56–0.82), respectively. The cut-off values of CSA-m, MUR, and MRR were 12 mm² (sensitivity, 81.3%; specificity, 81.8%), 2.6 (sensitivity, 68.8%; specificity, 69.7%), and 10 (sensitivity, 65.6%; specificity, 63.6%), respectively.

Conclusions

: MUR and MRR had acceptable diagnostic abilities but did not show superiority over CSA-m for CTS diagnosis.

Ultrasound reference values for peripheral nerve cross-sectional areas and indices in a sample of healthy individuals in Brazil

Objective

To establish peripheral nerve cross-sectional area (CSA) reference values (absolute values, measures of asymmetry, and measures of focality) for healthy individuals in Brazil.

Materials and Methods

Sixty-six healthy volunteers underwent high-resolution ultrasound of the peripheral nerves. We obtained CSA measurements for three peripheral nerves, at specific locations: the median nerve, in the carpal tunnel (MT); the ulnar nerve, at the cubital tunnel site (UT) and at the pre-tunnel site (UPT); and the common fibular nerve, near the fibular head (FH). We calculated the CSA indices between the same sites on different sides (ΔCSAs) and between the ulnar nerve tunnel and pre-tunnel sites on the same side (ΔTPT).

Results

A total of 132 neural sites were analyzed, and the following CSA values (mean ± SD, median) were obtained: MT (6.3 ± 1.9 mm², 6.0 mm²); UT (6.2 ± 1.6 mm², 6.1 mm²); UPT (5.6 ± 1.7 mm², 5.4 mm²); and FH (10.0 ± 3.7 mm², 9.9 mm²). The ΔCSA values (mean ± SD, median) were as follows: MT (0.85 ± 0.7 mm², 0.95); UT (0.81 ± 0.62 mm², 0.95); UPT (0.61 ± 0.51 mm², 0.5); and FH (1.0 ± 0.77 mm², 1.0). The ΔTPT (mean ± SD, median) was (1.0 ± 0.8 mm², 1.0).

Conclusion

Among individuals in Brazil, peripheral nerve CSA values tend to be higher among males and to increase with aging. However, the same does not appear to hold true for the ΔCSA or the ΔTPT, the exception being the difference between the right and left UT. Differences in CSA values greater than 2.5 mm² between sides or between sites along the same nerve can indicate asymmetry or focal thickening in neuropathy, respectively.

Ultrasound of the Radial Nerve: A Pictorial Review

This pictorial review focuses on the ultrasound (US) appearance of the normal and pathological radial nerve (RN) and its branches and provides tips with which to locate them and avoid misinterpretation of normal findings. A wide range of our pathological cases are reviewed and presented to help in familiarizing the reader with common and uncommon clinical scenarios that affect the RN and its main branches.

Cross-Sectional Area Reference Values for Sonography of Peripheral Nerves in Taiwanese Adults

Background: Neuromuscular ultrasound is a complementary technology that aids in the diagnosis of peripheral neuropathy. The interpretation of neuromuscular ultrasound results requires the use of accurate normative cross-sectional area (CSA) reference values. This study aims to provide CSA reference values specific to Taiwanese adults for Sonography of peripheral nerves in the upper and lower extremities.

Methods: The study cohort included 66 healthy subjects (36 women; 30 men). A linear probe was used to measure the CSA of the median, ulnar, radial, tibial, sural, and peroneal nerves at multiple sites. These data were analyzed to determine standard ranges for the CSA at each site (reference range = mean ± 2 × SD) and identify correlations between the CSA and patient characteristics.

Results: Normative CSA ranges were determined for all the assessed nerve sites, revealing that the nerve sizes in this Taiwanese population were smaller than Caucasian populations but comparable to those reported for other Asian cohorts. Men tended to have larger nerves than women, even after adjusting for height and weight. The size of ulnar nerve in the cubital tunnel and the peroneal nerve in the popliteal fossa correlated negatively with increasing age. The nerve size correlated positively with increasing weight and BMI at several sites, correlation of median nerve in the forearm with weight and BMI was significant after multiple testing. Significant correlation was also found between size of ulnar nerve in cubital tunnel and decreasing height.

Conclusion: We provide reference ranges for neuromuscular ultrasound CSA values for the upper and lower extremities that are specific to the Taiwanese population. These reference values may be useful for evaluating peripheral neuropathy in Taiwanese subjects.

Normal anatomy, variants and factors associated with the cervical vagus nerve topography: a high-resolution ultrasound study

PURPOSE

To describe the cervical vagus nerve (CVN) topography at the thyroid lobe (TL) level using high-resolution ultrasound and to investigate the possible association with anthropometric data, TL size, and thyroid disease.

METHODS

We prospectively examined 550 CVNs in 275 (205 female, 70 male) individuals with normal thyroid (53/275, 19.3%), multinodular disease (167/275, 60.7%), and Hashimoto thyroiditis (55/275, 20%). The CVN location relative to the common carotid artery was recorded as typical (lateral position) and atypical (anterior, medial, and posterior position). The shortest distance between CVN and TL margin, the TL dimensions, and volume were measured.

RESULTS

Normal thyroid subjects had lateral-positioned right CVNs in 100% and lateral/anterior/medial left CVNs in 81.1%, 15.1%, and 3.8%, respectively. CVN types did not differ significantly bilaterally between study groups. Asymmetry in CVN topography in all subjects was found in 22.2%, of which anterior CVN was the most common atypical position (64%), especially on the left side (82%). Significant gender, age, body mass, and BMI differences among CVN types were observed on the left side only. Among CVN types, no difference in TL dimensions, volume, and CVN-TL distance was found in all study groups. A weak negative correlation was recorded between CVN-thyroid distance and TL volume only on the left side (r = - 0.147, p = 0.01).

CONCLUSION

Asymmetry in CVN topography is mainly due to the increased incidence of the anterior location of CVN on the left side. Age and anthropometric parameters are different on the left side possibly due to the increased prevalence of left CVN variants.

Problem Solved: Integral Applications of Musculoskeletal Ultrasound

Musculoskeletal ultrasound has grown substantially in use over the past several years as an indispensable companion to magnetic resonance imaging and other imaging modalities. This article reviews 10 integral applications of musculoskeletal ultrasound as a problem-solving tool with correlative case examples. These applications include the following: (1) accessibility and portability, (2) targeted imaging, (3) dynamic imaging, (4) contralateral comparison, (5) Doppler imaging, (6) increased spatial resolution, (7) solid versus cystic comparison, (8) posttraumatic imaging, (9) postsurgical imaging, and (10) treatment delivery and optimization. The review will help the radiologist recognize the complementary uses of musculoskeletal ultrasound with radiography, computed tomography, and magnetic resonance imaging.

Reference values for the cross-sectional area of normal radial nerve at two levels using high-resolution ultrasonography

Aim of the study

High-resolution ultrasound is less often used to evaluate the radial nerves. The radial nerve is often involved in entrapment syndromes. The aim of the study is to establish the reference values for the cross-sectional area of the normal radial nerve on high-resolution ultrasonography, and to identify relationships between the cross-sectional area and the subject’s age, gender, height, weight, body mass index, and hand dominance.

Material and methods

The study was conducted on 200 subjects of both sexes, between 18 and 75 years of age, who did not have history of peripheral neuropathy or trauma to the upper limb. High-resolution real-time sonographic examination of the radial nerves was performed in both arms at two different levels. Level 1 was taken just proximal to the nerve bifurcation, and level 2 just after the nerve exits the spiral grove.

Results

The mean cross-sectional area measured at level 2 (4.3 ± 0.4 mm²) was greater than that measured at level 1 (2.3 ± 0.3 mm²). No significant relationship was seen with age and hand dominance (p >0.05), but the cross-sectional area values at above mentioned levels were larger in males than in females (p <0.05). In addition, the cross-sectional areas of the radial nerves showed a positive correlation with height, weight, and body mass index (p <0.05).

Conclusion

The established ultrasonographic reference values along with basic clinical data will aid in the diagnosis, response to treatment, and prognostic evaluation of peripheral neuropathies.

Cross-sectional area reference values for high-resolution ultrasonography of the upper extremity nerves in healthy Asian adults

In this study, multiple-site, cross-sectional area (CSA) reference values were established for major peripheral nerves, including small branches, in the upper extremity of a healthy Asian population.This study included 107 prospectively recruited age-matched, healthy subjects with a mean age of 46 years (range, 24-75 years). All subjects underwent standardized nerve conduction studies for the median, ulnar, peroneal, posterior tibial, and sural nerves. CSA was measured unilaterally at 21 sites of the median, ulnar, radial, posterior interosseous, superficial radial sensory, musculocutaneous, lateral antebrachial cutaneous, and medial antebrachial cutaneous nerves.According to their age, the subjects were assigned to the younger group (20-40 years, n = 40), the middle group (40-59 years, n = 40), and the older group (60-80 years, n = 27). The significant differences of CSA values between age groups were found only at certain sites, such as the median (wrist, P = .003), ulnar (medial epicondyle, P = .031; forearm, P = .022), radial (antecubital fossa, P = .037), and superficial radial sensory nerve (P = .028). The CSA significantly correlated with gender, height, weight, and body mass index.This study provides CSA reference values for nerves, including small sensory nerves in the upper extremity, which can be useful in the ultrasonographic investigation of various peripheral neuropathies in the upper extremity.

Sonographic Evaluation of Peripheral Sciatic Nerve Injury: A Case Study

Traumatic peripheral nerve injury is not a common finding in the general population but is increasingly being recognized and diagnosed in trauma and emergency medicine settings. Peripheral nerve injury can cause temporary or long-term motor and sensory loss, as well as intense pain and disability, if left untreated. The cause of peripheral nerve injury is diverse and often involves soft tissue damage, fractures, and hemorrhage in cases of traumatic injury. Peripheral nerve injury does not always heal spontaneously and, depending on severity, may warrant surgical intervention and repair. Although electrodiagnosic testing and surgical exploration are considered gold standards for peripheral nerve injury, high-resolution sonographic examination supplemented by clinical findings may be of value. The use of sonography demonstrated utility in determining a strategic management timeline and the efficacy of a surgical intervention.

Median nerve travel and deformation in the transverse carpal tunnel increases with chuck grip force and deviated wrist position

Background

We assessed median nerve travel and deformation concurrently to better understand the influence of occupational risk factors on carpal tunnel dynamics, including forceful chuck gripping and deviated wrist positions.

Methods

Fourteen healthy right-hand dominant participants performed a chuck grip in 6 experimental conditions: two relative force levels (10% and 40% of maximum voluntary effort); three wrist positions (15° radial deviation, 0° neutral, 30° ulnar deviation). Chuck grip forces were measured with a load cell while the transverse cross-section of the carpal tunnel was imaged via ultrasound at the distal wrist crease. Images of the median nerve were analyzed in ImageJ to assess cross-sectional area, circularity, width, and height as well as travel in the anterior-posterior and medial-lateral axes.

Results

We found a main effect of deviated wrist position on both anterior-posterior and medial-lateral travel, with the greatest nerve travel occurring in 30° ulnar deviation. There was also a significant interaction between chuck grip force and deviated wrist position on cross-sectional area. Specifically, the area decreased with 40% vs. 10% chuck grip force when the wrist was in 30° ulnar deviation; however, there were no changes in 0° neutral and 15° radial deviation.

Discussion

Overall, we demonstrated that forceful chuck gripping in deviated wrist positions influenced carpal tunnel dynamics, resulting in both migratory and morphological changes to the median nerve. These changes may, in turn, increase local strain and stress with adjacent structures in the carpal tunnel. Future studies mapping contact stress between structures may further elucidate injury development of work-related carpal tunnel syndrome.

Nerve Ultrasound as Helpful Tool in Polyneuropathies

Background: Polyneuropathies (PNP) are a broad field of diseases affecting millions of people. While the symptoms presented are mostly similar, underlying causes are abundant. Thus, early identification of treatable causes is often difficult. Besides clinical data and basic laboratory findings, nerve conduction studies are crucial for etiological classification, yet limited. Besides Magnetic Resonance Imaging (MRI), high-resolution nerve ultrasound (HRUS) has become a noninvasive, fast, economic and available tool to help distinguish different types of nerve alterations in neuropathies. Methods: We aim to describe typical ultrasound findings in PNP and patterns of morphological changes in hereditary, immune-mediated, diabetic, metabolic and neurodegenerative PNP. Literature research was performed in PubMed using the terms ‘nerve ultrasound’, neuromuscular ultrasound, high-resolution nerve ultrasound, peripheral nerves, nerve enlargement, demyelinating, hereditary, polyneuropathies, hypertrophy’. Results: Plenty of studies over the past 20 years investigated the value of nerve ultrasound in different neuropathies. Next to nerve enlargement, patterns of nerve enlargement, echointensity, vascularization and elastography have been evaluated for diagnostic terms. Furthermore, different scores have been developed to distinguish different etiologies of PNP. Conclusions: Where morphological alterations of the nerves reflect underlying pathologies, early nerve ultrasound might enable a timely start of available treatment and also facilitate follow up of therapy success.

Lateral epicondylitis: Are we missing out on radial nerve involvement? A cross-sectional study

INTRODUCTION

Lateral epicondylitis (LE) is a common ailment causing pain and functional limitations. There is an inadequate understanding of its etiopathogenesis. Involvement of the radial nerve (RN) as the primary causative factor for this condition remains debatable. The aim of the present study was to assess the RN thickness in patients with LE and compare it with the unaffected side.

METHODS

The study included seventy eligible patients (M:F, 22:48) in the age group of 30-60 years with a clinical diagnosis of LE. The cross-sectional area of RN was measured at the spiral groove (SG) and around the antecubital fossa (AF) using ultrasound and compared with the unaffected side. Numeric Pain Rating Scale (NPRS) and the QuickDASH scale were used to assess pain and functional impairment.

RESULTS

Thickness of RN at the AF (p = 0.026) and the SG (p = 0.0117) on the affected were statistically significant compared to the unaffected side in the cohort comprising of all the 70 patients. Out of 70 patients, increased thickness was seen in 23 at the SG and 19 at the AF. QuickDASH was statistically significant in patients who had thickened nerves compared to the unaffected side at the SG (p = 0.04) but not at the AF (p = 0.16). NPRS was not statistically significant at either the AF (p = 0.34) or the SG (p = 0.71) in patients with thickened nerves.

CONCLUSION

Tennis elbow needs to be no longer acknowledged only as tendinopathy. It also requires consideration of the involvement of the RN.

Efficacy of a local corticosteroid injection on pain, disability and radial nerve thickness in patients with lateral epicondylitis

Introduction:

The aim of this study was to compare the effect of a steroid injection with conservative therapy (CT) versus CT alone on pain, functional limitations and the cross-sectional area (CSA) of the radial nerve (RN) in patients with lateral epicondylitis (LE).

Methods:

In this clinical trial, seventy subjects in the age group of 30–60 years with a clinical diagnosis of LE were recruited. Patients received an ultrasound-guided steroid injection and CT (Group A, n = 35) or CT alone (Group B, n = 35). Pain intensity (numeric pain rating scale), functional limitations (Quick Disabilities of the Arm, Shoulder, and Hand questionnaire) and the CSA of RN (mm²) using ultrasound were assessed at baseline, 4 and 12 weeks.

Results:

There was a significant difference in pain intensity (P < 0.05) at 4 weeks in favour of Group A but not at 12 weeks. A statistically significant difference was not present favouring either group concerning disability at both the follow-ups. The difference in CSA of the RN at the affected side in both groups A and B was not statistically significant at either the spiral groove or the antecubital fossa at baseline or the subsequent follow-ups.

Conclusions:

The CT with a steroid injection proved to be more efficacious in the short term concerning pain intensity and functional limitations. The RN thickness is not increased in patients with LE, thereby refuting its role to some extent in the pathogenesis of LE.

Nerve ultrasound reference data in children from two to seven years

OBJECTIVE

We examined selected peripheral and spinal nerves of children aged between two and seven years.

METHOD

High resolution ultrasound was performed in 116 children (2-7 years of age) at 19 predefined landmarks of median, ulnar, tibial, fibular, sural and radial nerves, the vagus as well as cervical spinal nerve 5 and 6. Further, side-to-side measuring and grey-scale analysis was done at selected nerve sites.

RESULTS

Nerves of children were on average smaller than those of adults. Nerve growth correlates significantly with age in all nerves, the mean values were similar in the age of two to four years and five to seven years. Body mass index (BMI) and gender showed moderate effect at some nerve sites, however not uniformly in all. A side-to-side difference of up to 30% in median, and up to 20% in tibial nerve can occur in healthy individuals. Grey-scale analysis for echointensity has been performed in median, ulnar and tibial nerves.

CONCLUSION

Nerve size increases with age, BMI and gender have moderate effect. A side-to-side-difference of up to 30% can exist.

SIGNIFICANCE

Reference values of nerve cross-sectional area, side-to-side-difference and echo intensity are necessary to detect nerve pathology in children as well as in adults.

Painful Traumatic Neuromas in Subcutaneous Fat: Visibility and Morphologic Features With Ultrasound

OBJECTIVES

Subcutaneous neuromas usually result from trauma and may lead to dissatisfaction in patients with a trigger point, loss of sensitivity in the relevant territory of innervation, and spontaneous neuropathic pain. Confirming clinically suspected cases of neuroma may prove difficult. The objective of this study was to evaluate the visibility and morphologic features of traumatic subcutaneous neuromas of the limbs with ultrasound (US).

METHODS

Between January 2012 and August 2016, 38 consecutive patients clinically suspected of having subcutaneous neuromas were investigated with US. The diagnosis was confirmed on the basis of a focal morphologic abnormality of the nerve associated with trigger pain. Each neuroma was classified into 1 of 3 subtypes based on its injury pattern. The subtypes were terminal neuroma, spindle neuroma, and scar encasement, either isolated or associated with these subtypes.

RESULTS

Forty-four lesions were found in the 38 patients, including 29 spindle neuromas (65.9%), 14 terminal neuromas (31.8%) and 1 scar encasement with no nerve caliber abnormality (2.3%). Fifteen neuromas (35% of all neuromas) were associated with scar encasement. In 13 cases that required surgery, the diagnosis of neuroma or scar encasement could be surgically proven and confirmed the validity of the US findings.

CONCLUSIONS

Ultrasound can be used to show and classify subcutaneous nerves of the upper and lower limbs with high accuracy. The US trigger sign provides an indication of neuroma involvement in pain. This modality can play a substantial role both in the preoperative planning of neuroma surgery and in therapeutic US-guided procedures.

Ankle and Foot Ultrasound: Reliability of Side-to-Side Comparison of Small Anatomic Structures

OBJECTIVES

In sonography of clinically relevant small structures of the ankle and foot, the healthy contralateral side can be used as a reference to identify subtle abnormalities. Intrasubject side-to-side variability must be minimal. The aim of this study was to assess the reliability of side-to-side sonographic evaluation of small structures of the ankle and foot.

METHODS

Thirty healthy volunteers were prospectively studied. Small structures of the ankle and foot were evaluated bilaterally by 2 musculoskeletal radiologists in separate sessions. The deep peroneal nerve, superior extensor retinacula, calcaneofibular ligament, superior peroneal retinacula, tibialis posterior tendon, tibial nerve, Achilles tendon, plantaris tendon, plantar fascia, and sural nerve were considered. To assess intra- and interreader agreements, 30 (100%) examinations were repeated. A nonparametric statistic was used.

RESULTS

Data were not normally distributed (P > .001). Intrareader agreement was k = 0.67 (95% confidence interval, 0.57-0.78) and interreader agreement was k = 0.73 (95% confidence interval, 0.68-0.77). The mean values and standard deviation for all the structures were 0.36 ± 1.85 mm. The overall coefficient of variation was 18.5%. The intraclass correlation coefficient was 0.93 (95% confidence interval, 0.92-0.94).

CONCLUSIONS

In ankle and foot sonography, the healthy contralateral side can be used as a reference during a real-time musculoskeletal ultrasound evaluation of small structures.

Clinical and Ultrasonographic Features of Distal Ulnar Neuropathy: A Review

Focal ulnar neuropathy at the wrist is a rare but problematic disorder often associated with the unique anatomy of this nerve as it courses through Guyon's canal, a superficial fibro-osseous tunnel in the proximal ulnar palm. The electrophysiologic features of this disorder have been well-characterized, but the sonographic anatomy of the nerve across the wrist and palm has yet to be systematically described in normal and abnormal states. In this review, we describe the basic anatomy and the sonographic appearance of the nerve in the wrist and palm in normals and individuals with pathology. The value of using US in conjunction with electrodiagnostic testing is emphasized as the two tests together provide critical information regarding etiology, predisposing factors, and functional significance. Furthermore, ultrasound is useful as a patient educational tool to promote behavioral changes that assist in nerve recovery when pathology is related to repetitive stress.

Nerve ultrasound: A reproducible diagnostic tool in peripheral neuropathy

OBJECTIVE

To determine interobserver variability of nerve ultrasound in peripheral neuropathy in a prospective, systematic, multicenter study.

METHODS

We enrolled 20 patients with an acquired chronic demyelinating or axonal polyneuropathy and 10 healthy controls in 3 different centers. All participants underwent an extensive nerve ultrasound protocol, including cross-sectional area measurements of median, ulnar, fibular, tibial, and sural nerves, and brachial plexus. Real-time image acquisition was performed blind by a local and a visiting investigator (reference). Five patients were investigated using different types of sonographic devices. Intraclass correlation coefficients were calculated, and a random-effects model was fitted to identify factors with significant effect on interobserver variability.

RESULTS

Systematic differences between measurements made by different investigators were small (mean difference 0.11 mm2 [95% confidence interval 0.00-0.23 mm2]). Intraclass correlation coefficients were generally higher in arm nerves (0.48-0.96) than leg nerves (0.46-0.61). The hospital site and sonographic device did not contribute significantly to interobserver variability in the random-effects model.

CONCLUSIONS

Interobserver variability of nerve ultrasound in peripheral neuropathy is generally limited, especially in arm nerves. Different devices and a multicenter setting have no effect on interobserver variability. Therefore, nerve ultrasound is a reproducible tool for diagnostics in routine clinical practice and (multicenter) research.

Relationship between sonographically measured median nerve cross-sectional area and presence of peripheral neuropathy in diabetic subjects

BACKGROUND

Neuropathy is a common complication of diabetes mellitus resulting from direct damage by hyperglycemia to the nerves and/or ischemia by microvascular injury to the endoneurial vessels which supply the nerves. Median nerve is one of the peripheral nerves commonly affected in diabetic neuropathy. The median nerve size has been studied in non-Nigerian diabetic populations. In attempt to contribute to existing literature, a study in a Nigerian population is needed.

AIM

To evaluate the cross-sectional area (CSA) of the median nerve using B-mode ultrasonography (USS) and the presence of peripheral neuropathy (PN) in a cohort of adult diabetic Nigerians.

METHODS

Demographic and anthropometric data of 85 adult diabetes mellitus (DM) and 85 age- and sex-matched apparently healthy control (HC) subjects were taken. A complete physical examination was performed on all study subjects to determine the presence of PN and modified Michigan Neuropathy Screening Instrument (MNSI) was used to grade its severity. Venous blood was taken from the study subjects for fasting lipid profile (FLP), fasting blood glucose (FBG) and glycated haemoglobin (HbA1c) while their MN CSA was evaluated at a point 5 cm proximal to (5cmCATL) and at the carpal tunnel (CATL) by high-resolution B-mode USS. Data was analysed using SPSS version 22.

RESULTS

The mean MN CSA was significantly thicker in DM subjects compared to the HC at 5cmCATL (P < 0.01) and at the CATL (P < 0.01) on both sides. The presence of diabetic peripheral neuropathy (DPN) further increased the MN CSA at the CATL (P < 0.05) but not at 5cmCATL (P > 0.05). However, the severity of DPN had no additional effect on MN CSA 5 cm proximal to and at the CATL. There was no significant association between MN CSA and duration of DM and glycemic control.

CONCLUSION

Thickening of the MN CSA at 5cmCATL and CATL is seen in DM. Presence of DPN is associated with worse thickening of the MN CSA at the CATL but not at 5cmCATL. Severity of DPN, duration of DM, and glycemic control had no additional effect on the MN CSA.

Sonographic evaluation of uncommonly assessed upper extremity peripheral nerves: anatomy, technique, and clinical syndromes

Targeted ultrasound of the median, ulnar, and radial nerves is a well-established technique for suspected upper extremity peripheral neuropathy. However, sonographic imaging of the brachial plexus and smaller peripheral nerve branches is more technically difficult and the anatomy is less familiar to many radiologists. As imaging techniques improve, many clinicians refer patients for imaging of previously less-familiar structures. In addition, some patients may present with injuries that could involve local neurovascular structures. Finally, patients presenting with isolated peripheral neuropathies may be referred for perineural injections with local anesthetic for diagnostic purposes, or steroid for therapeutic reasons. This requires sonologists to have a firm understanding of the courses of these nerves and the surrounding anatomic landmarks that can be used to accurately identify and characterize them. We discuss clinical syndromes referable to specific peripheral nerve branches in the upper extremity, the relevant anatomy, and sonographic technique.

Reliability of bedside ultrasound of limb and diaphragm muscle thickness in critically ill children

INTRODUCTION

We evaluated the reliability of measuring muscle thickness with ultrasound in limbs and diaphragms of critically ill children and determined the sensitivity of these measures to quantitate muscle atrophy over time.

METHODS

An expert and trained novice sonographers prospectively measured limb and diaphragm muscle thickness in 33 critically ill children.

RESULTS

Expert and novice intrarater and interrater reliability were similar. Intraclass correlations (ICC) and coefficients of variation (CoV) were better in limbs (ICC > 0.9; CoV 3.57%-5.40%) than in diaphragm (ICC > 0.8; CoV novice 11.88%, expert, 12.28%). Mean relative difference in all muscles was small (1%-8%). Limits of agreement of the relative difference were smaller in limb (<13%-18%) than in diaphragm (<38%) muscles.

DISCUSSION

Muscle thickness is reliably measured with ultrasound by trained examiners in critically ill children. Our approach detects atrophy >13% in limb and >38% in diaphragm muscles. The smaller detectable change in limb muscles is likely due to their greater thickness. Muscle Nerve 59:88-94, 2019.

Wrist and Hand Ultrasound: Reliability of Side-to-Side Comparisons of Very Small (<2-mm) Clinically Relevant Anatomic Structures

OBJECTIVES

In ultrasound (US) examinations of clinically relevant very small structures of the wrist and hand, the healthy contralateral side can be used as a reference to identify subtle abnormalities. Intraindividual side-to-side variability must be minimal. The aim of this study was to assess the reliability of side-to-side US evaluations of very small structures of the wrist and hand.

METHODS

Forty-one healthy volunteers were prospectively studied. Small structures of the wrist and hand were evaluated bilaterally by 2 musculoskeletal radiologists in separate sessions. The first annular pulleys of the second finger and the thumb, sagittal band of the third finger, extensor and flexor retinacula, ulnar collateral ligament of the thumb, radial collateral ligament of the second finger, and palmar cutaneous branches of the median and ulnar nerves were considered. To assess intra- and inter-reader agreement, 10 of 41 (24%) examinations were repeated. Nonparametric statistics were used.

RESULTS

Data were not normally distributed (P > .001). Intra-reader agreement was κ = 0.674 (95% confidence interval [CI], 0.57-0.78), and inter-reader agreement was κ = 0.935 (95% CI, 0.92-0.95). The mean value ± SD for all of the structures was 0.78 ± 0.44 mm. The overall coefficient of variation was 9.8% ± 0.07%. The intraclass correlation coefficient was 0.97 (95% CI, 0.96-0.98).

CONCLUSIONS

In clinical practice, the healthy contralateral side can be used as a reference during a real-time musculoskeletal US evaluation of small (<2-mm) structures.

Investigation of the Diagnostic Value of Ultrasonography for Radial Neuropathy Located at the Spiral Groove

Objective

To determine a diagnostic cut-off value for the cross-sectional area (CSA) of the radial nerve using ultrasonography for radial neuropathy located at the spiral groove (SG).

Methods

Seventeen patients with electrodiagnostic evidence of radial neuropathy at the SG and 30 healthy controls underwent ultrasonography of the radial nerve at the SG . The CSAs at the SG were compared in the patient and control groups. The CSA at the SG between the symptomatic and asymptomatic sides (ΔSx–Asx and Sx/Asx, respectively) were analyzed to obtain the optimal cut-off value. The relationship between the electrophysiological severity of radial neuropathy and CSA was also evaluated.

Results

Among the variables examined, there were statistically significant differences in the CSA between the patient and control groups, ΔSx–Asx, and Sx/Asx at the SG. In a receiver operating characteristics analysis, the cut-off CSA was 5.75 mm² at the SG (sensitivity 52.9%, specificity 90%), 1.75 mm² for ΔSx–Asx (sensitivity 58.8%, specificity 100%), and 1.22 mm² for Sx/Asx (sensitivity 70.6%, specificity 93.3%) in diagnosing radial neuropathy at the SG. There was no significant correlation between CSA and electrophysiological severity score for either patient group.

Conclusion

The reference value obtained for CSA of the radial nerve at the SG may facilitate investigation of radial nerve pathologies at the SG.

Dimensional changes of the carpal tunnel and the median nerve during manual mobilization of the carpal bones

INTRODUCTION

The carpal tunnel is a clinically important fibro-osseous conduit for the median nerve and associated tendons. It is mechanically dynamic, such that the dimensions of the tunnel and median nerve change with position, movement and application of externally applied force with mechanical devices. Therapeutic manual techniques that appear to move and change tunnel shape are part of clinical practice. The aim of this study was therefore to measure changes in dimensions of the carpal tunnel and median nerve with manual mobilization of the carpal bones.

MATERIAL AND METHODS

An analytical descriptive study with 18 volunteer subjects and a total of 33 records was designed. Ultrasound measurements of the cross-sectional area (CSA), anteroposterior diameter (APD), transverse diameter (TD), perimeter, flattening ratio and circularity of the carpal tunnel and of the median nerve, were measured, both in the anatomical position of the wrist and during mobilization techniques of the carpal bones.

RESULTS

During the mobilization technique, the tunnel (p = 0.003) CSA significantly increased. APD also increased significantly for the tunnel (<0.001) while TD decreased. The median nerve showed similar and significant (p < 0.001) changes than the tunnel. However, because several of the obtained differences where smaller than the SDD obtained in a previous study, these differences were considered as irrelevant.

CONCLUSIONS

Manual mobilization of the carpal bones produced significant changes in the dimensions of the carpal tunnel.

A review of main anatomical and sonographic features of subcutaneous nerve injuries related to orthopedic surgery

Lesion to subcutaneous nerves is a well-known risk of orthopedic surgery and a significant cause of postoperative pain and dissatisfaction in patients. High-resolution ultrasound can be used to visualize the vast majority of small subcutaneous nerves of the upper and lower limbs. Ultrasound detects nerve abnormalities such as focal hypoechoic thickening, stump neuroma, and scar encasement, and provides information not only about the peripheral nerve itself but also about its relationship to adjacent anatomical structures. The purpose of this review is to provide an overview of the anatomy of the main subcutaneous nerves damaged during orthopedic surgery, recall at-risk procedures, and offer useful anatomic landmarks to help the sonographer identify and follow the nerves when an iatrogenic lesion is suspected.

Nerve ultrasound in polyneuropathies

Ultrasound can be used to visualize pathology in the peripheral nerves of patients with polyneuropathy. Nerve enlargement is the most frequent pathology, but other abnormalities, including abnormal nerve echogenicity and vascularity, are also encountered. This monograph presents an overview of the role of nerve ultrasound in the evaluation and management of both inherited and acquired polyneuropathies. A description of the sonographic techniques and common abnormalities is provided, followed by a presentation of typical findings in different neuropathies. Scoring systems for characterizing the presence and pattern of nerve abnormalities as they relate to different polyneuropathies are presented. Muscle Nerve 57: 716-728, 2018.

Reliability of measurement of the carpal tunnel and median nerve in asymptomatic subjects with ultrasound

BACKGROUND

Morphology of the carpal tunnel changes with varying wrist postures and compressive forces applied to the wrist. These changes may affect the morphology and pressure on the median nerve and could be used as part of the treatment of the carpal tunnel syndrome patients. Reliability of the ultrasonographic measurements of the median nerve has been widely studied. However, there is a lack of investigation regarding reliability of ultrasonographic measurements of the carpal tunnel.

OBJECTIVE

The purpose of this study was to assess intra-tester and inter-tester reliability of measurement of dimensions of the carpal tunnel and median nerve with ultrasound in asymptomatic volunteers.

DESIGN

A cross-sectional methodological study.

METHODS

Aspects measured were mediolateral and anteroposterior diameters, flattening ratio, circularity, perimeter and cross-section area of the carpal tunnel and median nerve.

RESULTS

Intra-tester reliability was excellent for the carpal tunnel (ICCs from 0.91 to 0.97) and for the median nerve (ICCs from 0.79 to 0.94) measurements. The flattening ratio of the median nerve showed good agreement (ICC = 0.68). Inter-tester reliability was excellent for the carpal tunnel measurements (ICCs from 0.76 to 0.95) and, for the cross sectional area, the perimeter and mediolateral diameter of the median nerve, the ICC values were 0.89, 0.84 and 0.81, respectively.

CONCLUSION

In the context of this study, ultrasound was a reliable instrument for measuring carpal tunnel and median nerve dimensions in asymptomatic subjects.

LEVEL OF EVIDENCE

1b.

Estimation of ultrasound reference values for the upper limb peripheral nerves in adults: A cross-sectional study

The objective of this study is to estimate the reference values for the upper limb peripheral nerves in adults.The demographics and physical characteristics of 69 adult healthy volunteers were evaluated and recorded. In addition, the side to side differences of the estimated reference values and their correlations with the age, weight, height, and body mass index (BMI) were evaluated.Cross-sectional area reference values of the upper limb nerves did not correlate with height; however, they correlated with age, weight, and BMI in some scanned sites.The data obtained in this study could be helpful in future diagnosis of peripheral nerve disorders of the upper limb.

Ultrasonographic Evaluation of the Radial Nerves in Patients with Unilateral Refractory Lateral Epicondylitis

Objective

To evaluate the possible radial nerve entrapment of patients with unilateral refractory lateral epicondylitis (LE) by using ultrasound (US) and electroneuromyography.

Design

Cross-sectional study.

Setting

Three physical medicine and rehabilitation departments.

Subjects

Consecutive 44 patients (15 M, 29 F) with unilateral refractory LE.

Methods

All patients underwent detailed clinical, electrophysiological and ultrasonographic evaluations. Ultrasound imaging was used to evaluate thickness and presence of abnormal findings of the common extensor tendon (CET) and cross-sectional area (CSA) of the radial nerve (at spiral groove and before bifurcation) bilaterally. Unaffected sides of the patients were taken as controls.

Results

When compared with the unaffected sides, CET thickness and radial nerve CSAs (at both levels) were higher, and abnormal US findings regarding LE (47.7% vs. 6.8%) were more common on the affected sides than nonaffected sides (all P  < 0.001). Grip strength values were lower on the affected sides ( P  < 0.001). Electrophysiological studies were all normal, and similar between the two sides (all P  > 0.05). When subgroup analyses were performed after taking into account the hand dominance, affected and dominant sides were found to be the same in 31 and different in 13 patients. In subgroups, CETs and radial nerve CSAs at both levels were higher on the affected sides (all P  < 0.01).

Conclusions

Radial nerves and the CETs seem to be swollen on the affected sides, independent from the hand dominance of the patients with refractory LE. These results morphologically support the previous literature that attributes some of the chronic complaints of these patients actually to radial nerve entrapment.

Ultrasound versus MRI in common fibular neuropathy

INTRODUCTION

We prospectively compared ultrasound (US) and MRI in patients with common fibular neuropathy.

METHODS

Forty adult patients with clinical suspicion of common fibular neuropathy and 40 healthy controls underwent both US and MRI. US and MRI datasets were randomized for prospective reading.

RESULTS

The overall sensitivity of US and MRI for diagnosing fibular neuropathy was 90% (95% confidence interval [CI], 79.7%-97.3%) and 87.5% (95% CI, 71.55%-93.1%), respectively. The overall specificity of US and MRI was 92% (95% CI, 77.45%-96.1%) and 85% (95% CI, 73.3%-94.4%), respectively. The overall sensitivity and specificity of US combined with MRI were 94% (95% CI, 0.80%-0.99%) and 84% (95% CI, 0.70%-0.91%), respectively. Overall intra- and inter-observer agreements among 3 readers were 0.76% (95% CI, 0.62%-0.85%) and 0.74% (95% CI, 0.65%-0.81%).

CONCLUSIONS

US diagnostic accuracy for common fibular neuropathy was slightly higher than that of MRI. Muscle Nerve 55: 849-857, 2017.

Reproducibility of Ultrasonographic Measurements of the Ulnar Nerve at the Cubital Tunnel

The cross-sectional area (CSA) of the ulnar nerve is thought to be indicative of ulnar nerve entrapment. The purpose of the study was to determine reproducibility of ultrasonographic measurements of CSA of the ulnar nerve at the cubital tunnel in healthy adults. Two sonographers tested 69 participants using a standardized protocol. The inter-rater reliability intra-class correlation coefficient was 0.63, and the intra-rater reliability intra-class correlation coefficient was 0.85 for sonographer 1 and 0.88 for sonographer 2. The smallest detectable changes were 2.47 and 2.63 mm² (25% and 26% of the mean CSA). The mean difference and 95% limits of agreement for sonographers 1 and 2 were -0.13 (-2.56 to 2.29) and -0.38 (-2.93 to 2.18). Based on the fair to good inter-rater reliability, the excellent intra-rater reliability and the clinical applicable intra-rater agreement, ultrasonography seems to be a valuable tool with which to assess the CSA of the ulnar nerve for diagnostic and evaluative purposes.

Diffusion Tensor Imaging Tractography in Pure Neuritic Leprosy: First Experience Report and Review of the Literature

Five years after both right ulnar and median nerve decompression for paraesthesias and palsy, a patient, coming from Nigeria but living in Italy, came to our unit claiming to have persistent pain and combined median and ulnar palsy. Under suspicion of leprosy, skin and left sural nerve biopsy were performed. Skin tests were negative, but Schwann cells resulted as positive for acid-fast bacilli (AFB), leading to the diagnosis of Pure Neuritic Leprosy (PNL). The patient was given PB multidrug therapy and recovered from pain in two months. After nine months both High Resolution Ultrasonography (HRUS) and Magnetic Resonance Imaging (MRI) were performed, revealing thickening of the nerves. Since demyelination is common in PNL, the Authors started to use Diffusion Tensor Imaging Tractography (DTIT) to get better morphological and functional data about myelination than does the traditional imaging. DTIT proved successful in showing myelin discontinuity, reorganization, and myelination, and the Authors suggest that it can give more information about the evolution of the disease, as well as further indications for surgery (nerve decompression, nerve transfers, and babysitting for distal effector protection), and should be added to traditional imaging tools in leprosy.

Assessing the Reliability of Ultrasound Imaging to Examine Radial Nerve Excursion

Ultrasound imaging allows cost effective in vivo analysis for quantifying peripheral nerve excursion. This study used ultrasound imaging to quantify longitudinal radial nerve excursion during various active and passive wrist movements in healthy participants. Frame-by-frame cross-correlation software allowed calculation of nerve excursion from video sequences. The reliability of ultrasound measurement of longitudinal radial nerve excursion was moderate to high (intraclass correlation coefficient range = 0.63-0.86, standard error of measurement 0.19-0.48). Radial nerve excursion ranged from 0.41 to 4.03 mm induced by wrist flexion and 0.28 to 2.91 mm induced by wrist ulnar deviation. No significant difference was seen in radial nerve excursion during either wrist movement (p > 0.05). Wrist movements performed in forearm supination produced larger overall nerve excursion (1.41 ± 0.32 mm) compared with those performed in forearm pronation (1.06 ± 0.31 mm) (p < 0.01). Real-time ultrasound is a reliable, cost-effective, in vivo method for analysis of radial nerve excursion.